Gram negative bacteria, including strains of Escherichia coli and Salmonella, are hazardous to human health, particularly when food items are contaminated with them. In addition to the health affects on those who consume contaminated food, outbreaks of illness associated with bacteria contamination represent a major adverse economic threat to food industries, particularly when production must be halted to identify the source of the contamination, and when products already released into the market must be recalled.
Certain attempts have been made to introduce an effective “kill-step” into the line of production for foods, including subjecting food to various chemicals or radiation that may be partially lethal to the pathogens. However, these methods have proven to be less than ideal solutions because they do not guaranty a high enough rate of effectiveness, and also because they subject food to residues that present their own health impacts and/or interference with flavor, etc.
Therefore it is desirable to achieve a so-called “kill-step” that eliminates most, if not all, bacteria pathogens from food. It is also desirable that such a “kill-step” be relatively inexpensive, and—when possible—be effectuated by apparatus that can be retro-fitted to existing food production equipment for produce, meat, dairy, and other foodstuffs.
Some basic definitions of the scientific principles involved in the process may be helpful at this point. Electrical current effects changes in cell surface properties. These changes occur by affecting the following: surface hydrophobicity, net surface electrostatic and all surface shapes and polymers. Hydrophobicity is explained as a “dislike and like” of the microbial to water. Hydrophobic interactions define the strong attraction between hydrophobic molecules and surfaces in water. This hydrophobicity determines adherence to surfaces. Polysaccharides, proteins and amino acids are all hydrophobic in nature and make up the compounds of the cell walls. The net negative surface electrical charge is increased under DC applications and determines the interaction between bacteria cell, surfaces, and DC currents.
Electric DC current can change cell movement from surfaces. This is because bacteria cells are generally negatively charged which dictates their electrophoresis movement in DC currents. In essence, it overrides and energizes the internal governing system at the surface level and causes instant absorption of H2O into the cell and blows up the cell, similar to a balloon filled with water. When bacterial species are exposed to DC electrical current or fields, they affect cell surfaces and cell shapes. This process also involves electro kinetics. Electro kinetics is the application of a weak DC current or potential to soil or products or aquifer and water. The mode of action through the cell surface hydrophobicity plays out through electrical current causing cell shape change and increases the net negative surface electrical charge. This change affects extracellular polymers as well as Hydrophobicity, which, is greatly increased after DC current applications. DC current can and does increase the negative surface electrostatic charge causing H2O to rush in burst and flatten the cell walls.
Once the cell wall is saturated with DC current, irreversible permualization of the cell wall occurs then oxidation reduction takes place to finish bacteria off. Electric DC current effects orientation of the membrane lipids and through electrical application causes irreversible permeabilization of the cell wall. DC current also produces oxidation reduction agents such as chlorine and hydrogen peroxide.